MELBOURNE (Reuters) - Defending champion Novak Djokovic was knocked out of the second round of the Australian Open on Thursday by Uzbek wildcard Denis Istomin, losing 7-6(8) 5-7 2-6 7-6(5) 6-4 at Rod Laver Arena.

It was six-times champion Djokovic's earliest elimination from Melbourne Park since his first round exit in 2006.